Extracted Text

The following text was automatically extracted from the image on this page using optical character recognition software:

eV both in experiments and sX-LDA. For InN the correction of sX-LDA is more pronounced.The recently experimentally measured band gap for WZ structure is 0.8 eV. [4] The sX-LDAresult for WZ InN is 0.89 eV, which is in the same quality as in the many-body GW method.The LDA band gap, on the other hand, is negative and predicts a qualitatively incorrectmetallic state. Another effect of sX-LDA on the band structures of both GaN and AlN isthe increase of the valence band width by ~i 2 eV, which has been observed in other bulksemiconductors. [11]To model the disordered zinc-blende Ga In1_ N alloy with Ga molar fraction 0 < x < 1,we employed the special quasi-random structures (SQSs). [20] SQSs are finite model systemsconstructed to mimic the radial correlation functions of an infinite random structure. Theyhave been extensively used to study the electronic structures of alloys. We considered twoclasses of model systems of SQS8 and SQS16. In SQS8 the cell consists of n In, n Ga, and8 N atoms with n + n = 8. In SQS16 the cell contains twice the number of atoms in SQS8.For each model system, the lattice constant was inferred from experimental lattice constantusing Vegard's law.[21] The equilibrium atom positions were obtained by minimizing thetotal energy within LDA. A total of 16 k-point were used to integrate over SQS Brillouinzone for SQS8. Table II shows that the band gap difference between SQS8 and SQS16 isless than 0.1 eV for all alloy compounds. Further increase of SQS cell size does not changeTABLE I: Band gap of GaN and InN in zinc-blende and wurtzite crystal structures. Energy is ineV.